A press conference is set for Thursday morning, according to Fox Sports.com.

Porter, 40, is currently the third base coach for the Washington Nationals and has held that position for the past two seasons. Before that Porter was the third base coach and bench coach with the Arizona Diamondbacks (in 2010) and a third base coach for the then-Florida Marlins (from 2007 to 2009).

Since the Nationals will be in the playoffs, Porter will not begin to work for the Astros until Washington is eliminated from the playoffs, according to Fox Sports.com

DeFrancesco was named interim manager on Aug. 19, a day after the team fired Brad Mills as its manager.

The Astros have the worst record in baseball at 51-105. The team is one in rebuilding mode under first-year general manager Jeff Luhnow, who traded high-salaried veterans Carlos Lee, Wandy Rodriguez, Brett Myers and Brandon Lyon before the July 31 trading deadline.

The franchise will also be shifting leagues next season from the National League to the American League. The Astros will be the fifth team in the AL West division, bring the total number of teams to 15 in each league.